Effects of Relative Humidity and Spraying Medium on UV Decontamination of Filters Loaded with Viral Aerosols

Woo, Myung-Heui; Grippin, Adam; Anwar, Diandra; Smith, Tamara; Wu, Chang‐Yu; Wander, Joseph D.

doi:10.1128/aem.00465-12

Cited by 51 publications

(52 citation statements)

References 28 publications

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“…For MS2, Q␤, and X174, k values of 0.28, 0.44, and 2.02 cm 2 /mJ were calculated, respectively, and X174 showed the highest UV sensitivity among the studied viruses. This result is consistent with a study investigating loss of viral infectivity following UVC LED water and air disinfection in which X174 demonstrated higher sensitivity than MS2 (23,25,32,33). Dimerization of thymine in DNA and uracil in RNA by UVC irradiation occurred not to the same degree, because absorption spectra of the nucleotides showed different peak wavelengths.…”

Section: Resultssupporting

confidence: 90%

“…Griffiths et al reported a 1.6-log reduction of MS2 by a heating, ventilation, and air conditioning (HVAC) system incorporating 6 UV lamps (no irradiation dose specified) (24). Also, an approximately 3-log reduction of MS2 dispersed in beef extract medium solution and artificial saliva occurred when treated with 7,200 mJ/cm 2 in an air disinfection system (25). Surviving populations and fitted curves for E. coli O157:H7, S. Typhimurium, L. monocytogenes, and S. aureus are presented in Fig.…”

Section: Resultsmentioning

confidence: 99%

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UVC LED Irradiation Effectively Inactivates Aerosolized Viruses, Bacteria, and Fungi in a Chamber-Type Air Disinfection System

Kim

Kang

2018

Appl Environ Microbiol

156

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In this study, the possibility of inactivating viral, bacterial, and fungal aerosols in a chamber-type air disinfection system by using a UVC light-emittingdiode (LED) array was investigated and inactivation rate constants of each microorganism were calculated in fitting curves of surviving populations. UVC LED array treatment effectively inactivated viral infectivity, achieving 5-log reductions within 45 mJ/cm 2 for MS2, Q␤, and X174 viruses. UVC LED array effectiveness in inactivating Escherichia coli O157:H7, Salmonella enterica serovar Typhimurium, Listeria monocytogenes, and Staphylococcus aureus aerosols achieved 2.5-to 4-log reductions within 1.5 to 4.6 mJ/cm 2 . Also, 4-log reductions of Aspergillus flavus and Alternaria japonica were achieved at a dosage of 23 mJ/cm 2 using UVC LED array irradiation. The highest UV susceptibility, represented by the inactivation rate constant, was calculated for bacteria, followed by fungi and viruses. UVC LED, an innovative technology, can effectively inactivate microorganisms regardless of taxonomic classification and can sufficiently substitute for conventional mercury UV lamps. IMPORTANCE The United Nations Environment Programme (UNEP) convened the Minamata Convention on Mercury in 2013 to ban mercury-containing products in order to ensure human and environmental health. It will be effectuated in 2020 to discontinue use of low-pressure mercury lamps and new UV-emitting sources have to replace this conventional technology. However, the UV germicidal irradiation (UVGI) system still uses conventional UV lamps, and no research has been conducted for air disinfection using UVC LEDs. The research reported here investigated the inactivation effect of aerosolized microorganisms, including viruses, bacteria, and fungi, with an UVC LED module. The results can be utilized as a primary database to replace conventional UV lamps with UVC LEDs, a novel type of UV emitter. Implementation of UVC LED technology is truly expected to significantly reduce the extent of global mercury contamination, and this study provides important baseline data to help ensure a healthier environment and increased health for humanity.

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Section: Resultssupporting

confidence: 90%

Section: Resultsmentioning

confidence: 99%

UVC LED Irradiation Effectively Inactivates Aerosolized Viruses, Bacteria, and Fungi in a Chamber-Type Air Disinfection System

Kim

Kang

2018

Appl Environ Microbiol

156

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“…An added complication is that viruses are often damaged/inactivated during collection using air samplers, due to the stresses and forces acting upon them. 24,[28][29][30][31] To be able to evaluate and compare different methods for detecting viable viral aerosols, our first goal was to develop a system that could safely, efficiently, and consistently generate aerosolized influenza virus. The viral aerosol-generation system was coupled with a bioaerosol sampler for characterizing airborne particles associated with viable influenza viruses.…”

Section: Introductionmentioning

confidence: 99%

Collection and measurement of aerosols of viable influenza virus in liquid media in an Andersen cascade impactor

Fennelly¹,

Tribby²,

Wu³

et al. 2014

VAAT

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“…To better simulate the generation of virus aerosols from human saliva, several researchers have developed a recipe for making artificial saliva and have used it as a nebulizer suspension (10)(11)(12)(13). The same artificial saliva was later adopted by ASTM to evaluate the decontamination efficacy of air-permeable materials and surfaces challenged with bioaerosols (14,15).…”

mentioning

confidence: 99%

Survival of Airborne MS2 Bacteriophage Generated from Human Saliva, Artificial Saliva, and Cell Culture Medium

Zuo

Kuehn

Bekele

et al. 2014

Appl Environ Microbiol

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c Laboratory studies of virus aerosols have been criticized for generating airborne viruses from artificial nebulizer suspensions (e.g., cell culture media), which do not mimic the natural release of viruses (e.g., from human saliva). The objectives of this study were to determine the effect of human saliva on the infectivity and survival of airborne virus and to compare it with those of artificial saliva and cell culture medium. A stock of MS2 bacteriophage was diluted in one of three nebulizer suspensions, aerosolized, size selected (100 to 450 nm) using a differential mobility analyzer, and collected onto gelatin filters. Uranine was used as a particle tracer. The resulting particle size distribution was measured using a scanning mobility particle sizer. The amounts of infectious virus, total virus, and fluorescence in the collected samples were determined by infectivity assays, quantitative reverse transcription-PCR (RT-PCR), and spectrofluorometry, respectively. For all nebulizer suspensions, the virus content generally followed a particle volume distribution rather than a number distribution. The survival of airborne MS2 was independent of particle size but was strongly affected by the type of nebulizer suspension. Human saliva was found to be much less protective than cell culture medium (i.e., 3% tryptic soy broth) and artificial saliva. These results indicate the need for caution when extrapolating laboratory results, which often use artificial nebulizer suspensions. To better assess the risk of airborne transmission of viral diseases in real-life situations, the use of natural suspensions such as saliva or respiratory mucus is recommended.T he potential involvement of virus aerosols in the transmission of human respiratory diseases, although still under considerable debate, has led to increased public concern. Several studies have found that a variety of respiratory viruses, including influenza virus and severe acute respiratory syndrome (SARS) coronavirus, could be present at high concentrations in human saliva and respiratory mucus (1-3). When infected individuals cough, sneeze, speak, or simply breathe, particles of saliva and/or respiratory mucus that carry viruses can be easily generated (4, 5), resulting in an increased risk of viral infection by aerosols.In an effort to understand and control transmission of viral diseases via aerosols, researchers have generated airborne viruses in laboratories to study their infectivity and survival (i.e., the ability to remain infectious) since the 1930s. Laboratory-generated virus aerosols are commonly produced from liquid suspensions using pneumatic nebulizers such as Collison nebulizers, as the wet-dispersion technique simulates many dispersion processes of viruses in the natural environment (6). However, the composition of liquid suspensions from which virus aerosols are generated (also known as nebulizer suspensions) is known to affect the infectivity/survival of airborne viruses (7,8). Given that many laboratory studies use artificial nebulizer suspensi...

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Effects of Relative Humidity and Spraying Medium on UV Decontamination of Filters Loaded with Viral Aerosols

Cited by 51 publications

References 28 publications

UVC LED Irradiation Effectively Inactivates Aerosolized Viruses, Bacteria, and Fungi in a Chamber-Type Air Disinfection System

UVC LED Irradiation Effectively Inactivates Aerosolized Viruses, Bacteria, and Fungi in a Chamber-Type Air Disinfection System

Collection and measurement of aerosols of viable influenza virus in liquid media in an Andersen cascade impactor

Survival of Airborne MS2 Bacteriophage Generated from Human Saliva, Artificial Saliva, and Cell Culture Medium

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